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Johnson wedge wire screen cylinders operate on the principle of V-shaped profile wires wound around longitudinal support rods, creating continuous, non-blinding slots. The wedge-shaped profile creates slots that widen inwardly, allowing particles that pass through the slot opening to exit the screen without becoming trapped. This design reduces clogging compared to perforated metal or woven wire mesh alternatives.
The cylindrical configuration supports two flow directions: outside-to-inside flow for most intake and filtration applications, and inside-to-outside flow for rotary screens and dewatering drums. Each wire intersection is permanently bonded through resistance welding, creating a rigid structure that maintains consistent slot dimensions under pressure differentials up to 150psi.
Production begins with precision cold-drawn V-shaped wire and round support rods. Wires are positioned on automated winding machines that maintain consistent slot tolerance of ±0.02mm for slots under 0.5mm, and ±0.05mm for larger slots. Each contact point between surface wire and support rod receives an electrical resistance weld, fusing the components without filler material.
Following welding, cylinders are sized to precise diameter tolerances of ±0.5mm, then cut to length and finished with end connections. All units undergo pressure testing and slot verification before shipment to ensure conformance to ordered specifications.
Specification |
Details |
|---|---|
Construction Type |
Internal axial surface wire with external circumferential support rods |
Slot Size Range |
0.05mm - 10mm |
Standard Diameter Range |
25mm - 1200mm |
Maximum Single Section Length |
6 meters |
Welding Method |
Electrical resistance welding |
Support Rod Profiles |
Round wire, triangular wire |
Standard End Connections |
Flanged, threaded, welded ring |
Available Flow Directions |
Outside-in, inside-out |
Open Area Range |
5% - 40% depending on slot size |
Material selection is determined by operating environment and fluid compatibility:
Stainless steel 304/304L: General purpose water applications, ambient temperature service
Stainless steel 316/316L: Chloride-containing water, mild chemical service
Duplex stainless steel 2205/2207: Seawater service, high pressure differential applications
Hastelloy C276: Strong acid and chemical processing environments
Titanium alloy T2: Desalination, chlorine dioxide service, high corrosion applications
All materials are sourced from certified mills with material test reports available for commercial procurement documentation.
These cylinders serve filtration and separation functions across multiple industrial applications:
Water well intake screens for groundwater extraction
Trommel screens and rotary drum screens for mineral processing
Centrifuge baskets for solid-liquid separation
Dewatering screens for coal and aggregate processing
Starch and food processing separation equipment
Pulp and paper mill screening applications
Wastewater treatment intake and effluent screens
Oil and gas well sand control screens
The smooth internal surface reduces friction loss and facilitates cleaning via mechanical scrapers or backwashing.
Slot size is selected based on sieve analysis of the aquifer formation, typically sized to retain 90% of the formation sand while maintaining maximum open area.
Collapse pressure varies with diameter, wall thickness, and slot size. Standard 200mm diameter screens with 0.5mm slots withstand 1.0MPa external pressure.
NPT, BSP, and metric threads are available as standard. Custom flange dimensions per ANSI, DIN, or JIS standards can be manufactured to order.
Heavy-duty configurations with additional support rods or external reinforcement bands are available for vibrating screen and high-pressure applications.
